Broadcasting of digital television (DTV) signals is prevailing worldwide. DTV and conventional analog televisions (ATV) are now coexistent. FIG. 1 shows a block diagram of a conventional digital/analog TV receiver 1. The receiver 1 comprises a tuner 10, a demodulator 12, and a decoder 14. The demodulator 12 and the decoder 14 of the conventional receiver 1 are respectively disposed on separate print circuit boards (PCBs), between which a coaxial line 16 is installed for signal transmission. To impedance-match 75Ω of the coaxial line of the receiver 1, two 75Ω precision resistors 18 are applied on two PCBs of the demodulator 12 and the decoder 14. Further, the demodulator 12 also requires a precision reference resistor Rref, so that an accurate circuit output current is generated and stability of an output voltage is maintained.
For that the demodulator 12 and the demodulator 14 are disposed on two separate PCBs, the receiver 1 is easily interfered by noises such that its area cannot be reduced. In addition, even if the precision resistors 18 are utilized in the receiver 1, an output voltage swing of the demodulator 12 may still have a noticeable variation due to manufacture errors of a die-to-die procedure and fluctuations of a power supply voltage, thus much likely leading to errors in signal transmission.
Therefore, a digital/analog TV receiver capable of suppressing noise interferences is in need for minimizing the variation of an output voltage swing of a decoder.